I have three predefined lists in Google Maps (Favorites, Want to go and Starred places). When I try to save any location to the first two I get an error "Failed to save to Favorites" or "Failed to save to Want to go". However, I can save successfully to the Starred places.
Also, when I try to create my own list using "New list" I get a "Failed to create list" error.
The error messages come from the bottom of the page in a dark grey box, like this:
So, why can't I use these features? This is not a one-time thing, I've been trying to do this for a couple of weeks now and get the same issue.
EDIT: Just found out that the feature works when I am connected to the internet via VPN selecting a server in Latvia for example. As soon as I'm disconnected and get back to my local server in Azerbaijan the feature stops working. So it can be a region-based problem maybe?